Hydrogen-generating fuel cell cartridges

ABSTRACT

The present application is directed to a gas-generating apparatus and various pressure regulators or pressure-regulating valves. Hydrogen is generated within the gas-generating apparatus and is transported to a fuel cell. The transportation of a first fuel component to a second fuel component to generate of hydrogen occurs automatically depending on the pressure of a reaction chamber within the gas-generating apparatus. The pressure regulators and flow orifices are provided to regulate the hydrogen pressure and to minimize the fluctuation in pressure of the hydrogen received by the fuel cell. Connecting valves to connect the gas-generating apparatus to the fuel cell are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.10/629,006, filed Jul. 29, 2003, U.S. application Ser. No. 11/067,167,filed on Feb. 25, 2005, U.S. provisional App. No. 60/689,538 filed onJun. 13, 2005, and U.S. provisional App. No. 60/689,539 filed on Jun.13, 2005, all of which are incorporated herein in their entireties byreference.

BACKGROUND OF THE INVENTION

Fuel cells are devices that directly convert chemical energy ofreactants, i.e., fuel and oxidant, into direct current (DC) electricity.For an increasing number of applications, fuel cells are more efficientthan conventional power generation, such as combustion of fossil fuel,as well as portable power storage, such as lithium-ion batteries.

In general, fuel cell technology includes a variety of different fuelcells, such as alkali fuel cells, polymer electrolyte fuel cells,phosphoric acid fuel cells, molten carbonate fuel cells, solid oxidefuel cells and enzyme fuel cells. Today's more important fuel cells canbe divided into several general categories, namely (i) fuel cellsutilizing compressed hydrogen (H₂) as fuel; (ii) proton exchangemembrane (PEM) fuel cells that use alcohols, e.g., methanol (CH₃OH),metal hydrides, e.g., sodium borohydride (NaBH₄), hydrocarbons, or otherfuels reformed into hydrogen fuel; (iii) PEM fuel cells that can consumenon-hydrogen fuel directly or direct oxidation fuel cells; and (iv)solid oxide fuel cells (SOFC) that directly convert hydrocarbon fuels toelectricity at high temperature.

Compressed hydrogen is generally kept under high pressure and istherefore difficult to handle. Furthermore, large storage tanks aretypically required and cannot be made sufficiently small for consumerelectronic devices. Conventional reformat fuel cells require reformersand other vaporization and auxiliary systems to convert fuels tohydrogen to react with oxidant in the fuel cell. Recent advances makereformer or reformat fuel cells promising for consumer electronicdevices. The most common direct oxidation fuel cells are direct methanolfuel cells or DMFC. Other direct oxidation fuel cells include directethanol fuel cells and direct tetramethyl orthocarbonate fuel cells.DMFC, where methanol is reacted directly with oxidant in the fuel cell,is the simplest and potentially smallest fuel cell and also haspromising power application for consumer electronic devices. SOFCconvert hydrocarbon fuels, such as butane, at high heat to produceelectricity. SOFC requires relatively high temperature in the range of1000° C. for the fuel cell reaction to occur.

The chemical reactions that produce electricity are different for eachtype of fuel cell. For DMFC, the chemical-electrical reaction at eachelectrode and the overall reaction for a direct methanol fuel cell aredescribed as follows:

Half-reaction at the anode:CH₃OH+H₂O→CO₂+6H⁺+6e⁻

Half-reaction at the cathode:1.5O₂+6H⁺+6e⁻→3H₂O

The overall fuel cell reaction:CH₃OH+1.5O₂→CO₂+2H₂O

Due to the migration of the hydrogen ions (H⁺) through the PEM from theanode to the cathode and due to the inability of the free electrons (e⁻)to pass through the PEM, the electrons flow through an external circuit,thereby producing an electrical current through the external circuit.The external circuit may be used to power many useful consumerelectronic devices, such as mobile or cell phones, calculators, personaldigital assistants, laptop computers, and power tools, among others.

DMFC is discussed in U.S. Pat. Nos. 5,992,008 and 5,945,231, which areincorporated by reference herein in their entireties. Generally, the PEMis made from a polymer, such as Nafion® available from DuPont, which isa perfluorinated sulfonic acid polymer having a thickness in the rangeof about 0.05 mm to about 0.50 mm, or other suitable membranes. Theanode is typically made from a Teflonized carbon paper support with athin layer of catalyst, such as platinum-ruthenium, deposited thereon.The cathode is typically a gas diffusion electrode in which platinumparticles are bonded to one side of the membrane.

In another direct oxidation fuel cell, borohydride fuel cell (DBFC)reacts as follows:

Half-reaction at the anode:BH₄-+8OH—→BO₂-+6H₂O+8e-

Half-reaction at the cathode:2O₂+4H₂O+8e-→8OH—

In a chemical metal hydride fuel cell, sodium borohydride is reformedand reacts as follows:NaBH₄+2H₂O→(heat or catalyst)→4(H₂)+(NaBO₂)

Half-reaction at the anode:H₂→2H⁺+2e⁻

Half-reaction at the cathode:2(2H⁺+2e⁻)+O₂→2H₂O

Suitable catalysts for this reaction include platinum and ruthenium, andother metals. The hydrogen fuel produced from reforming sodiumborohydride is reacted in the fuel cell with an oxidant, such as O₂, tocreate electricity (or a flow of electrons) and water by-product. Sodiumborate (NaBO₂) by-product is also produced by the reforming process. Asodium borohydride fuel cell is discussed in U.S. Pat. No. 4,261,956,which is incorporated by reference herein in its entirety.

One of the most important features for fuel cell application is fuelstorage. Another important feature is to regulate the transport of fuelout of the fuel cartridge to the fuel cell. To be commercially useful,fuel cells such as DMFC or PEM systems should have the capability ofstoring sufficient fuel to satisfy the consumers' normal usage. Forexample, for mobile or cell phones, for notebook computers, and forpersonal digital assistants (PDAs), fuel cells need to power thesedevices for at least as long as the current batteries and, preferably,much longer. Additionally, the fuel cells should have easily replaceableor refillable fuel tanks to minimize or obviate the need for lengthyrecharges required by today's rechargeable batteries.

One disadvantage of the known hydrogen gas generators is that once thereaction starts the gas generator cartridge cannot control the reaction.Thus, the reaction will continue until the supply of the reactants runout or the source of the reactant is manually shut down.

Accordingly, there is a desire to obtain a hydrogen gas generatorapparatus that is capable of self-regulating the flow of at least onereactant into the reaction chamber and other devices to regulate theflow of fuel.

SUMMARY OF THE INVENTION

The present application is directed to a gas-generating apparatus andvarious pressure regulators or pressure-regulating valves. Hydrogen isgenerated within the gas-generating apparatus and is transported to afuel cell. The transportation of a first fuel component to a second fuelcomponent to generate of hydrogen occurs automatically depending on thepressure of a reaction chamber within the gas-generating apparatus. Thepressure regulators, including flow orifices, are provided to regulatethe hydrogen pressure and to minimize the fluctuation in pressure of thehydrogen received by the fuel cell. Connecting valves to connect thegas-generating apparatus to the fuel cell are also provided.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings, which form a part of the specification andare to be read in conjunction therewith and in which like referencenumerals are used to indicate like parts in the various views:

FIG. 1 is a cross-sectional schematic view of a gas-generating apparatusaccording to the present invention; FIG. 1A is an enlarged partialcross-sectional view of a solid fuel container for use in thegas-generating apparatus of FIG. 1; FIG. 1B is an enlarged partialcross-sectional view of an alternate solid fuel container for use in thegas-generating apparatus of FIG. 1; FIG. 1C is an alternate embodimentof FIG. 1B; FIG. 1D is a cross-sectional view of an alternate embodimentof a fluid conduit;

FIG. 2A is a cross-sectional view of a shut-off or connection valve foruse in the gas-generating apparatus of FIG. 1 shown in the disconnectedand closed position; FIG. 2B is a cross-sectional view of the shut-offvalve shown in FIG. 2A shown in the connected and open position;

FIG. 3 is a cross-sectional view of a pressure-regulated fluid nozzle orvalve for use in the gas-generating apparatus of FIG. 1;

FIG. 4A is a cross-sectional view of a pressure-regulating valve for usein the gas-generating apparatus of FIG. 1; FIG. 4B is an explodedperspective view of the pressure-regulating valve of FIG. 4A; FIG. 4C isa cross-sectional view of an alternate pressure-regulating valve; FIG.4D is an exploded perspective view of the pressure-regulating valve ofFIG. 4C;

FIG. 5A is a cross-sectional view of another pressure-regulating valveconnected to a first valve component of the shut-off valve of FIG. 2;FIGS. 5B-D are cross-sectional views showing the pressure-regulatingvalve and the first valve component with a second valve component of theshut-off valve in the unconnected, connected/closed and connected/openpositions;

FIG. 6A is a cross-sectional view of a pressure-regulating valve for usein the gas-generating apparatus of FIG. 1; FIG. 6B is an exploded viewof the pressure-regulating valve of FIG. 6A; and

FIGS. 7A and 7B are cross-sectional views of a variable diameter orificefor use with the pressure-regulating valves of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

As illustrated in the accompanying drawings and discussed in detailbelow, the present invention is directed to a fuel supply, which storesfuel cell fuels, such as methanol and water, methanol/water mixture,methanol/water mixtures of varying concentrations, pure methanol, and/ormethyl clathrates described in U.S. Pat. Nos. 5,364,977 and 6,512,005B2, which are incorporated by reference herein in their entirety.Methanol and other alcohols are usable in many types of fuel cells,e.g., DMFC, enzyme fuel cells and reformat fuel cells, among others. Thefuel supply may contain other types of fuel cell fuels, such as ethanolor alcohols; metal hydrides, such as sodium borohydrides; otherchemicals that can be reformatted into hydrogen; or other chemicals thatmay improve the performance or efficiency of fuel cells. Fuels alsoinclude potassium hydroxide (KOH) electrolyte, which is usable withmetal fuel cells or alkali fuel cells, and can be stored in fuelsupplies. For metal fuel cells, fuel is in the form of fluid borne zincparticles immersed in a KOH electrolytic reaction solution, and theanodes within the cell cavities are particulate anodes formed of thezinc particles. KOH electrolytic solution is disclosed in U.S. Pat. App.Pub. No. US 2003/0077493, entitled “Method of Using Fuel Cell SystemConfigured to Provide Power to One or More Loads,” published on Apr. 24,2003, which is incorporated by reference herein in its entirety. Fuelscan also include a mixture of methanol, hydrogen peroxide and sulfuricacid, which flows past a catalyst formed on silicon chips to create afuel cell reaction. Moreover, fuels include a blend or mixture ofmethanol, sodium borohydride, an electrolyte, and other compounds, suchas those described in U.S. Pat. Nos. 6,554,877, 6,562,497 and 6,758,871,which are incorporated by reference herein in their entireties.Furthermore, fuels include those compositions that are partiallydissolved in a solvent and partially suspended in a solvent, describedin U.S. Pat. No. 6,773,470 and those compositions that include bothliquid fuel and solid fuels, described in U.S. Pat. Appl. Pub. No. US2002/0076602. Suitable fuels are also disclosed in co-owned, co-pendingU.S. Pat. Appl. No. 60/689,572, entitled “Fuels for Hydrogen-GeneratingCartridges,” filed on Jun. 13, 2005. These references are alsoincorporated by reference herein in their entireties.

Fuels can also include a metal hydride such as sodium borohydride(NaBH₄) and water, discussed above. Fuels can further includehydrocarbon fuels, which include, but are not limited to, butane,kerosene, alcohol, and natural gas, as set forth in U.S. Pat. Appl. Pub.No. US 2003/0096150, entitled “Liquid Hereto-Interface Fuel CellDevice,” published on May 22, 2003, which is incorporated by referenceherein in its entirety. Fuels can also include liquid oxidants thatreact with fuels. The present invention is therefore not limited to anytype of fuels, electrolytic solutions, oxidant solutions or liquids orsolids contained in the supply or otherwise used by the fuel cellsystem. The term “fuel” as used herein includes all fuels that can bereacted in fuel cells or in the fuel supply, and includes, but is notlimited to, all of the above suitable fuels, electrolytic solutions,oxidant solutions, gaseous, liquids, solids, and/or chemicals includingadditives and catalysts and mixtures thereof.

As used herein, the term “fuel supply” includes, but is not limited to,disposable cartridges, refillable/reusable cartridges, containers,cartridges that reside inside the electronic device, removablecartridges, cartridges that are outside of the electronic device, fueltanks, fuel refilling tanks, other containers that store fuel and thetubings connected to the fuel tanks and containers. While a cartridge isdescribed below in conjunction with the exemplary embodiments of thepresent invention, it is noted that these embodiments are alsoapplicable to other fuel supplies and the present invention is notlimited to any particular type of fuel supply.

The fuel supply of the present invention can also be used to store fuelsthat are not used in fuel cells. These applications can include, but arenot limited to, storing hydrocarbons and hydrogen fuels for microgas-turbine engines built on silicon chips, discussed in “Here Come theMicroengines,” published in The Industrial Physicist (December2001/January 2002) at pp. 20-25. As used in the present application, theterm “fuel cell” can also include microengines. Other applications caninclude storing traditional fuels for internal combustion engines andhydrocarbons, such as butane for pocket and utility lighters and liquidpropane.

Suitable known hydrogen-generating apparatus are disclosed incommonly-owned, co-pending U.S. Pat. Appl. Pub. No. US 2005-0074643 A1and U.S. Pat. Appl. Pub. No. US 2005-0266281, and co-pending U.S. patentapplication Ser. No. 11/066,573 filed on Feb. 25, 2005. The disclosuresof these references are incorporated by reference herein in theirentireties.

The gas-generating apparatus of the present invention may include areaction chamber, which may include an optional first reactant, and areservoir having a second reactant. The first and second reactants canbe a metal hydride, e.g., sodium borohydride, and water. The reactantscan be in gaseous, liquid, aqueous or solid form. Preferably, the firstreactant stored in the reaction chamber is a solid metal hydride ormetal borohydride with selected additives and catalysts such asruthenium, and the second reactant is water optionally mixed withselected additives and catalysts. Water and metal hydride of the presentinvention react to produce hydrogen gas, which can be consumed by a fuelcell to produce electricity. Other suitable reactants or reagents aredisclosed in the parent applications, previously incorporated above.

Additionally, the gas-generating apparatus can include a device orsystem that is capable of controlling the transport of a second reactantfrom the reservoir to the reaction chamber. The operating conditionsinside the reaction chamber and/or the reservoir, preferably a pressureinside the reaction chamber, are capable of controlling the transport ofthe second reactant in the reservoir to the reaction chamber. Forexample, the second reactant in the reservoir can be introduced into thereaction chamber when the pressure inside the reaction chamber is lessthan a predetermined value, preferably less than the pressure in thereservoir, and, more preferably less than the pressure in the reservoirby a predetermined amount. It is preferable that the flow of the secondreactant from the reservoir into the reaction chamber is self-regulated.Thus, when the reaction chamber reaches a predetermined pressure,preferably a predetermined pressure above the pressure in the reservoir,the flow of the second reactant from the reservoir into the reactionchamber can be stopped to stop the production of hydrogen gas.Similarly, when the pressure of the reaction chamber is reduced belowthe pressure of the reservoir, preferably below the pressure in thereservoir by a predetermined amount, the second reactant can flow fromthe reservoir into the reaction chamber. The second reactant in thereservoir can be introduced into the reaction chamber by any knownmethod including, but not limited to, pumping, osmosis, capillaryaction, pressure differential valves, other valve(s), or combinationsthereof. The second reactant can also be pressurized with springs orpressurized liquids and gases. Preferably, the second reactant ispressurized with liquefied hydrocarbons, such as liquefied butane.

Referring to FIG. 1, an inventive fuel supply system is shown. Thesystem includes a gas-generating apparatus 12 contained within a housing13 and is configured to be connected to a fuel cell (not shown) via afuel conduit 16 and a valve 34. Preferably, fuel conduit 16 initiateswithin gas-generating apparatus 12, and valve 34 is in fluidcommunication with conduit 16. Fuel conduit 16 can be a flexible tube,such as a plastic or rubber tube, or can be a substantially rigid partconnected to housing 13.

Within housing 13, gas-generating apparatus 12 preferably includes twomain compartments: a fluid fuel component reservoir 44 containing afluid fuel component 22 and a reaction chamber 18 containing a solidfuel component 24. Reservoir 44 and reaction chamber 18 are sealed offfrom one another until the production of a fuel gas, such as hydrogen,is desired by reacting fluid fuel component 22 with solid fuel component24. Housing 13 is preferably divided by interior wall 19 to form fluidreservoir 44 and reaction chamber 18.

Reservoir 44 may preferably, however, include a liner, bladder orsimilar fluid container 21 to contain fluid or liquid fuel component 22as shown. Fluid fuel component 22 preferably includes water and/or anadditive/catalyst or other liquid reactants. Additional appropriatefluid fuel components and additives are further discussed herein.Suitable additives/catalysts include, but are not limited to,anti-freezing agents (e.g., methanol, ethanol, propanol and otheralcohols), catalysts (e.g., cobalt chloride and other known catalysts),pH adjusting agents (e.g., acids such as sulfuric acid and other commonacids). Preferably, fluid fuel component 22 is pressurized, such as bysprings or by pressurized/liquefied gas (butane or propane), although itmay also be unpressurized. When liquefied hydrocarbon is used, it isinjected into reservoir 44 and is contained in the space between liner21 and housing 13.

Reservoir 44 and reaction chamber 18 are fluidly connected by a fluidtransfer conduit 88. Fluid transfer conduit 88 is connected to conduit15, which is in fluid communication with liquid fuel component 22 withinliner 21, and one or more conduits 17, which brings the liquid fuelcomponent 22 into contact with the solid fuel component 24. Orifice 15can be connected directly to conduit 88, or as shown in FIG. 1 it can beconnected to a channel 84 defined on the outside surface of plug 86which defines conduit 88 therewithin. Hole 87 connects surface channel84 to conduit 88. The function of plug 86 is further defined hereafter.Fluid transfer conduit 88 can also be a channel or similar void formedin housing 13, or external tubing located outside of housing 13. Otherconfigurations are also appropriate.

Reaction chamber 18 is contained within housing 13 and separated fromfluid fuel component reservoir 44 by interior wall 19 and is preferablymade of a fluid impenetrable material, such as a metal, for example,stainless steel, or a resin or plastic material. As liquid fuelcomponent 22 and solid fuel component 24 are mixed within reactionchamber 18 to produce a fuel gas, such as hydrogen, reaction chamber 18also preferably includes a pressure relief valve 52 located in housing13. Pressure relief valve 52 is preferably a pressure-triggered valve,such as a check valve or a duckbill valve, which automatically ventsproduced fuel gas should the pressure within reaction chamber, P₁₈,reach a specified triggering pressure. Another pressure relief valve canbe installed on fluid fuel component reservoir 44.

Solid fuel component 24, which can be powders, granules, or other solidforms, is disposed within a solid fuel container 23, which, in thisembodiment, is a gas permeable bladder, liner or bag. Fillers and otheradditives and chemicals can be added to solid fuel component 24 toimprove its reaction with the liquid reactant. Preferably, additivesthat can be corrosive to valves and other elements within fluid transferconduit 88, conduits 15 and 17 should be included with solid fuel 24.Solid fuel component 24 is packed inside solid fuel container 23, whichis preferably cinched or wrapped tightly around one or more fluiddispersion elements 89; for example with rubber or elastic bands, suchas rubber or metal bands, with heat shrunk wraps, pressure adhesivetapes or the like. Solid fuel container 23 can also be formed bythermoform. In one example, solid fuel container 23 comprises aplurality of films that are selectively perforated to control the flowof liquid reactant, gas and/or by-products therethrough. Each fluiddispersion element 89 is in fluid communication with conduits 17, withinwhich the liquid fuel is transported to the solid fuel. Dispersionelement 89 is preferably a rigid tube-like hollow structure made of anon-reactive material having openings 91 along its length and at its tipto assist in the maximum dispersal of fluid fuel component 22 to contactsolid fuel component 24. Preferably, at least some of the openings 91 influid dispersion element 89 include capillary fluid conduits 90, whichare relatively small tubular extensions to disperse the fluid even moreeffectively throughout solid fuel component 24. Capillary conduits 90can be fillers, fibers, fibrils or other capillary conduits. Each fluiddispersion element 89 is supported within reaction chamber 18 by a mount85, which is also the point at which fluid dispersion element 89 isconnected to conduits 17 and to fluid transfer conduit 88.

The inner diameter of fluid dispersion element 89 is sized anddimensioned to control the volume and speed that liquid fuel component22 is transported therethrough. In certain instances, the effectiveinner diameter of element 89 needs to be sufficiently small, such thatthe manufacture of such a small tube may be difficult or expensive. Insuch instances, a larger tube 89 a can be used with a smaller rod 89 bdisposed within the larger tube 89 a to reduce the effective innerdiameter of the larger tube 89 a. The liquid fuel component istransported through the annular space 89 c between the tube and theinner rod, as shown in FIG. 1D.

In another embodiment, to increase the permeability of the liquid fuelcomponent 22 through the solid fuel component 24, hydrophilic materials,such as fibers, foam chopped fibers or other wicking materials, can beintermixed with the solid fuel component 24. The hydrophilic materialscan form an interconnected network within solid fuel component 24, butthe hydrophilic materials do not need to contact each other within thesolid fuel component to improve permeability.

Solid fuel container 23 may be made of many materials and can beflexible or substantially rigid. In the embodiment shown in FIG. 1A,solid fuel container 23 is preferably made of a single layer 54 of agas-permeable, liquid impermeable material such as CELGARD® andGORE-TEX®. Other gas permeable, liquid impermeable materials usable inthe present invention include, but are not limited to, SURBENT®Polyvinylidene Fluoride (PVDF) having a porous size of from about 0.1 μmto about 0.45 μm, available from Millipore Corporation. The pore size ofSURBENT® PVDF regulates the amount of liquid fuel component 22 or waterexiting the system. Materials such as electronic vent-type materialhaving 0.2 μm hydro, available from W. L. Gore & Associates, Inc., mayalso be used in the present invention. Additionally, sintered and/orceramic porous materials having a pore size of less than about 10 μm,available from Applied Porous Technologies Inc., are also usable in thepresent invention. Additionally, or alternatively, the gas permeable,liquid impermeable materials disclosed in commonly owned, co-pendingU.S. patent application Ser. No. 10/356,793 are also usable in thepresent invention, all of which are incorporated by reference herein intheir entireties. Using such materials allows for the fuel gas producedby the mixing of fluid fuel component 22 and solid fuel component 24 tovent through solid fuel container 23 and into reaction chamber 18 fortransfer to the fuel cell (not shown), while restricting the liquidand/or paste-like by-products of the chemical reaction to the interiorof solid fuel container 23.

FIG. 1B shows an alternate construction for solid fuel container 23. Inthis embodiment, the walls of solid fuel container 23 are made ofmultiple layers: an outer layer 57 and an inner layer 56 separated by anabsorbent layer 58. Both inner layer 56 and outer layer 57 may be madeof any material known in the art capable of having at least one slit 55formed therein. Slits 55 are openings in inner layer 56 and outer layer57 to allow the produced fuel gas to vent from solid fuel container 23.To minimize the amount of fluid fuel component 22 and/or paste-likeby-products that may exit through slits 55, absorbent layer 58 ispositioned between inner layer 56 and outer layer 57 to form a barrier.Absorbent layer 58 may be made from any absorbent material known in theart, but is preferably capable of absorbing liquid while allowing gas topass through the material. One example of such a material is paper fluffcontaining sodium polyacrylate crystals; such a material is commonlyused in diapers. Other examples include, but are not limited to,fillers, non-wovens, papers and foams. As will be recognized by those inthe art, solid fuel container 23 may include any number of layers,alternating between layers containing slits 55 and absorbent layers.

In one example shown in FIG. 1C, solid fuel component 24 is encased infour layers 54 a, 54 b, 54 c and 54 d. These layers are preferably gaspermeable and liquid impermeable. Alternatively, each layer can be madefrom any material with a plurality of holes or slits 55, as shown, toallow the produced gas to pass through. Disposed between adjacent layers54 a-d are absorbent layers 58. In this embodiment, the flow path forthe produced gas and the by-products, if any, is made tortuous toencourage more liquid fuel component 22 to remain in contact with solidfuel component 24 longer to produce more gas. As shown, while theinnermost layer 54 a is perforated on both sides, the next layer 54 b isperforated only on one side. The next layer 54 c is also perforated onone side, but opposite to the perforated side of layer 54 b. Layer 54 dis perforated on one side, but opposite to the perforated side of layer54 c and so on. Alternatively, instead of using partially perforatedlayers 54 a-b wrapping around solid fuel component 24, liners or bagsmade with a permeable portion and non-permeable portion can be usedinstead, with the permeable portion of one liner located opposite fromthe permeable portion of the next outer layer.

Disposed within fluid transfer conduit 88 is preferably a fluid transfervalve 33 to control the flow of fluid fuel component 22 into reactionchamber 18. Fluid transfer valve 33 may be any type of pressure-opened,one-way valve known in the art, such as a check valve (as shown in FIG.1), a solenoid valve, a duckbill valve, a valve having a pressureresponsive diaphragm, which opens when a threshold pressure is reached.Fluid transfer valve 33 may be opened by user intervention and/ortriggered automatically by pressurized fluid fuel component 22. In otherwords, fluid transfer valve 33 acts as an “on/off” switch for triggeringthe transfer of fluid fuel component 22 to reaction chamber 18. In thisembodiment, a fluid transfer valve 33 is a check valve including abiasing spring 35 pushing a ball 36 against a sealing surface 37.Preferably, a deformable sealing member 39 such as an O-ring is alsoincluded to assure a seal. Shown as overlapped areas in FIG. 1 are theportions of valve 33 that would be compressed to form a seal. Plug 86,discussed above, is used in an exemplary method of assembling valve 33.A channel is formed in the bottom end of housing 13 for fluid transferconduit 88. First, spring 35 is inserted in this channel, followed byball 36 and sealing member 39. Plug 86 is finally inserted in thischannel to compress spring 35 and presses against ball 36 and sealingmember 39 to form a seal with valve 33. Parts of plug 86, i.e., hole 87and peripheral channel 84, connect fluid transfer conduit 88 to conduit15 to reach liquid fuel component 22.

In this embodiment, fluid transfer valve 33 opens when the fluidpressure within reservoir 44 exceeds the pressure of reaction chamber 18by a predetermined amount. As reservoir 44 is preferably pressurized,this triggering pressure is exceeded immediately upon pressurizingreservoir 44. To stop fluid transfer valve 33 from opening before fuelgas is desired to be produced, a stopping mechanism (not shown), such asa latch or a pull tab, may be included, so that the first user of fuelsupply 12 may start the transfer of fluid fuel component 22 by releasingthe stopping mechanism. Alternatively, chamber 18 is pressurized with aninert gas or hydrogen to equalize the pressure across valve 33 withinsaid predetermined amount.

Fuel conduit 16 is attached to housing 13 as shown by any method knownin the art. Optionally, a gas-permeable, liquid impermeable membrane 32may be affixed over the reaction chamber-facing side of conduit 16.Membrane 32 limits the amount of liquids or by-products from beingtransferred out of gas generating apparatus 12 to the fuel cell via fuelconduit 16. Fillers or foam can be used in combination with membrane 32to retain liquids or by-products and to reduce clogging. Membrane 32 maybe formed from any liquid impermeable, gas permeable material known toone skilled in the art. Such materials can include, but are not limitedto, hydrophobic materials having an alkane group. More specific examplesinclude, but are not limited to: polyethylene compositions,polytetrafluoroethylene, polypropylene, polyglactin (VICRY®),lyophilized dura mater, or combinations thereof. Gas permeable member 32may also comprise a gas permeable/liquid impermeable membrane covering aporous member. Such a membrane 32 may be used in any of the embodimentsdiscussed herein. Valve 34 can be any valve, such as apressure-triggered valve (a check valve or a duckbill valve) or apressure-regulating valve or pressure regulator described below. Whenvalve 34 is a pressure-triggered valve (such as valve 33), no fuel canbe transferred until P₁₈ reaches a threshold pressure. Valve 34 may bepositioned in fuel conduit 16 as shown in FIG. 1, or can be locatedremote from gas-generating device 12.

A connection valve or shut-off valve 27 may also be included, preferablyin fluid communication with valve 34. As shown in FIG. 2A, connectionvalve 27 is preferably a separable valve having a first valve component60 and a second valve component 62. Each valve component 60, 62 has aninternal seal. Further, first valve component 60 and second valvecomponent 62 are configured to form an intercomponent seal therebetweenbefore being opened. Connection valve 27 is similar to the shut-offvalves described in parent '006 application. Connection valve 27 isshaped and dimensioned for transporting gas.

First valve component 60 includes a housing 61 and housing 61 defines afirst flow path 79 through its interior. Disposed within first flow path79 is a first slidable body 64. Slidable body 64 is configured to sealfirst flow path 79 by pressing a sealing surface 69 against a deformablesealing member 70, such as an O-ring, disposed in first flow path 79near a shoulder 82 formed by the configuration of first flow path 79.Slidable body 64 is biased toward shoulder 82 formed on a second end offirst valve component 60 to secure the seal formed at sealing surface69. Slidable body 64 will remain in this biased position until firstvalve component 60 and second valve component 62 are engaged.Alternatively, slidable body 64 is made from an elastomeric material toform a seal and sealing member 70 can be omitted.

An elongated member 65 extends from one end of slidable body 64, asshown. Elongated member 65 is a needle-like extension that protrudesfrom housing 61. Elongated member 65 is preferably covered with atubular sealing surface 67. A space or void is formed in the annularspace between elongated member 65 and tubular sealing surface 67 toextend first flow path 79 outside of housing 61. Tubular sealing surface67 is connected to elongated member 65 with optional spacers or ribs(not shown) so as not to close off first flow path 79. Elongated member65 and tubular sealing surface 67 are configured to be inserted intosecond valve component 62.

Second valve component 62 is similar to first valve component 60 andincludes a housing 63 made of a substantially rigid material. Housing 63defines a second flow path 80 through its interior. Disposed withinsecond flow path 80 is a second slidable body 74. Slidable body 74 isconfigured to seal second flow path 80 by pressing a sealing surface 75against a deformable sealing member 73 near a shoulder 83. Slidable body74 is biased to the sealing position by spring 76. Second valvecomponent 62 thus remains sealed until first valve component 60 andsecond valve component 62 are correctly connected. Alternatively,slidable body 74 is made from an elastomeric material to form a seal andsealing member 73 can be omitted.

A pin 81 extends from the other end of slidable body 74. Pin 81 is aneedle-like extension and remains within housing 63, and does not sealsecond flow path 80. Pin 81 is also sized and dimensioned to engage withelongated member 65 when first valve component 60 and second valvecomponent 62 are engaged. A sealing member 71, such as an O-ring, may bepositioned between pin 81 and the interface end of second valvecomponent 62 so that a seal is formed around tubular sealing surface 67before and during the period when first valve component 60 and secondvalve component 62 are engaged.

To open first valve component 60 and second valve component 62 to form asingle flow path therethrough, first valve component 60 is inserted intosecond valve component 62 or vice versa. As the two valve components 60,62 are pushed together, elongated member 65 engages with pin 81, whichpress against each other to move first slidable body 64 away fromshoulder 82 and second slidable body 74 away from shoulder 83. As such,sealing members 70 and 73 are disengaged to allow fluid to flow throughfirst flow path 79 and second flow path 80, as shown in FIG. 2B.

First valve component 60 and second valve component 62 are configuredsuch that an inter-component seal is formed between tubular sealingsurface 67 and sealing member 71, before preferably either sealingsurface 69 of first slidable body 64 or sealing surface 75 of secondslidable body 74 are disengaged from sealing members 70 and 73,respectively.

A first end of housing 61 and a second end of housing 63 preferablyinclude barbs 92 a and 92 b, respectively, for easy and secure insertioninto fuel conduit 16. Alternatively, barbs 92 a and 92 b may be anysecure connector known in the art, such as threaded connectors or pressfit connectors. Additional configurations for connection valves are morefully described in the parent '006 application, also published as U.S.Pat. App. Pub. US 2005/0022883 A1, previously incorporated by reference.

Retainer 77 is positioned on the interface end of second valve component62. Retainer 77 may also be a sealing member, such as an O-ring, agasket, a viscous gel, or the like. Retainer/sealing member 77 isconfigured to engage front sealing surface 78 on first valve component60 to provide another inter-component seal.

One of valve components 60 and 62 can be integrated with a fuel supply,and the other valve component can be connected to a fuel cell or adevice powered by the fuel cell. Either valve component 60 and/or 62 canalso be integrated with a flow or pressure regulator orpressure-regulating valve, discussed below.

Before the first use, fluid transfer valve 33, as shown in FIG. 1, isopened either by removing a pull tab or latch or by removing the initialpressurized gas in chamber 18. Pressurized fluid fuel component 22 istransferred into reaction chamber 18 via fluid transfer conduit 88 toreact with solid fuel component 24. Pressurized fluid fuel component 22passes through an orifice 15 and into fluid transfer conduit 88. Whilefluid transfer valve 33 is opened, fluid fuel component 22 iscontinually fed into reaction chamber 18 to create the fuel gas that isthen transferred to the fuel cell or the device through fuel conduit 16.In one embodiment, to halt the production of additional gas, fluidtransfer valve 33 can be manually shut-off.

In another embodiment, one of several pressure-regulating devices may beemployed within gas-generating apparatus 12 to allow for the automaticand dynamic control of gas generation. This is accomplished in generalby allowing the reaction chamber pressure P₁₈ to control the inflow offluid fuel component 22 using fluid transfer valve 33 and/or one or morepressure-regulating valve 26, as described below.

In one embodiment, as shown in FIG. 3, pressure-regulating valve 26 ispositioned in mount 85 or conduits 17 and generally acts as an inletport between fluid transfer conduit 88 and fluid dispersion element 89.Pressure-regulating valve 26 can also be positioned in conduit 88 orconduit 15. An end of fluid dispersion element 89 is connected to acarrier 99, which is slidably disposed within mount 85. Near where fluidtransfer conduit 17 terminates, one end of carrier 99 is in contact witha globe seal 93 surrounding a jet 94. Jet 94 is fluidly connected toconduit 17, and globe seal 93 is configured to control the fluidconnection therebetween. As shown in FIG. 3, valve 26 is in an openconfiguration, so fluid would be able to flow from fluid transferconduit 88 into jet 94.

The other end of carrier 99 is connected to a pressure actuated systemincluding a diaphragm 96 exposed to reaction chamber 18 and reactionchamber pressure P₁₈, a spring 95 biasing diaphragm 96 towards reactionchamber 18, and a support plate 98. Carrier 99 is engaged with supportplate 98. Diaphragm 96 may be any type of pressure-sensitive diaphragmknown in the art, such as a thin rubber, metal or elastomeric sheet.When reaction chamber pressure P₁₈ increases due to the production offuel gas, diaphragm 96 tends to deform and expand toward the base ofmount 85, but is held in place by the force F₉₅ from spring 95. Whenreaction chamber pressure P₁₈ exceeds the biasing force F₉₅ provided byspring 95, diaphragm 96 pushes support plate 98 toward the base of mount85. As carrier 99 is engaged with support plate 98, carrier 99 alsomoves toward the base of mount 85. This motion deforms globe seal 93 toseal the connection between fluid transfer conduit 88 and jet 94,thereby cutting off the flow of fluid fuel component 22 into reactionchamber 18.

While valve 33 (shown in FIG. 1) is open, the operation ofgas-generating apparatus 12 may therefore happen in a dynamic andcyclical fashion to provide on demand fuel to the fuel cell. When valve33 is initially opened, reaction chamber pressure P₁₈ is low, sopressure-regulating valve 26 is fully open. Valves 33 and 26 may havesubstantially similar pressure differentials for opening and closing,and in the preferred embodiment one valve may act as a backup for theother. Alternatively, the opening pressure differentials may bedifferent, i.e., the differential pressure to open or close valve 33 maybe higher or lower than that of valve 26, to provide additional ways tocontrol the flow through conduit 88.

As fluid fuel component 22 is fed into reaction chamber via valve 26and/or valve 33 and fluid dispersal elements 89, the reaction betweenfluid fuel component 22 and solid fuel component 24 begins to generatefuel gas. Reaction chamber pressure P₁₈ gradually increases with thebuild up of fuel gas until threshold pressure P₃₄ is reached and valve34 opens to allow the flow of gas through fuel conduit 16. Fuel gas isthen transferred out of reaction chamber 18. While this process mayreach a steady state, the production of gas may outpace the transfer ofgas through valve 34, or, alternatively, valve 34 or another downstreamvalve may be manually closed by a user or electronically closed by thefuel cell or host device. In such a situation, reaction chamber pressureP₁₈ may continue to build until reaction chamber pressure P₁₈ exceedsthe force F₉₅ supplied by spring 95. At this point, diaphragm 96 deformstoward the base of mount 85, thereby driving carrier 99 toward the baseof mount 85. As described above, this action causes globe seal 93 toseal the connection between fluid transfer conduit 88 and jet 94. As noadditional fluid fuel component 22 may be introduced into reactionchamber 18, the production of fuel gas slows and eventually stops. Valve33 can also be closed by P₁₈, i.e., when P₁₈ exceeds P₄₄ or when thedifference between P₁₈ and P₄₄ is less than a predetermined amount,e.g., the amount of force exerted by spring 35.

If valve 34 is still open, or if it is re-opened, fuel gas is thentransferred out of reaction chamber 18, so that reaction chamberpressure P₁₈ decreases. Eventually, reaction chamber pressure P₁₈decreases below the force F₉₅ provided by spring 95, which pushessupport 98 toward reaction chamber 18. As support 98 is engaged withcarrier 99, carrier 99 also slides toward reaction chamber 18, whichallows globe seal 93 to return to its unsealed configuration.Consequently, additional fluid fuel component 22 begins to flow throughjet 94 and into reaction chamber via fluid dispersal element 89. Newfuel gas is produced, and reaction chamber pressure P₁₈ rises onceagain. Similarly, when P₁₈ is less than P₄₄, or is less than P₄₄ by apredetermined amount, then valve 33 opens to allow fluid fuel component22 to flow.

This dynamic operation is summarized below in Table 1, when valve 33 isopened manually, or when valve 33 and valve 26 have substantially thesame differential triggering pressure so that one valve backs up theother valve.

TABLE 1 Pressure Cycle of Gas-Generating Apparatus with Valve 33 Open orOmitted State of Gas Production, Pressure Condition of Pressure- inReaction Chamber Pressure Balance regulating Valve 26 18 P₄₄ > P₁₈ OPENGas production starts; F₉₅ > P₁₈ Pressure builds P₁₈ < P₃₄ P₄₄ ≧ P₁₈OPEN Gas production F₉₅ ≧ P₁₈ continues; Pressure P₁₈ = P₃₄ builds ifproduction outpaces outflow P₄₄ ≦ P₁₈ CLOSED Gas production slows F₉₅ ≦P₁₈ to halt; Pressure P₁₈ ≧ P₃₄ decreases P₄₄ > P₁₈ OPEN Gas productionstarts F₉₅ > P₁₈ again P₁₈ < P₃₄

TABLE 2 Pressure Cycle of Gas-Generating Apparatus with Valve 26 Open orOmitted State of Gas Production, Pressure Condition of Pressure- inReaction Chamber Pressure Balance regulating Valve 33 18 P₄₄ > P₁₈ OPENGas production starts; P₁₈ < P₃₄ Pressure builds P₄₄ ≧ P₁₈ OPEN Gasproduction P₁₈ = P₃₄ continues; Pressure builds if production outpacesoutflow P₄₄ ≦ P₁₈ CLOSED Gas production slows P₁₈ ≧ P₃₄ to halt;Pressure decreases P₄₄ > P₁₈ OPEN Gas production starts P₁₈ < P₃₄ again

Referring to FIGS. 4A and 4B, another suitable pressure regulator orregulating valve 126 is shown. Pressure-regulating valve 126 can bepositioned within fluid transfer conduit 88, similar to the positioningof fluid transfer valve 33 as shown in FIG. 1. Pressure-regulating valve126 is preferably placed in series with fluid transfer valve 33, orpressure-regulating valve 126 may replace fluid transfer valve 33. Valve126 can be used with other cartridges or hydrogen generators and can actas a pressure regulator. In another embodiment, regulating valve 126 canreplace valve 34. Regulating valve 126 can be connected to or be a partof the fuel cell or the device that houses the fuel cell. Regulatingvalve 126 can be located either upstream or downstream of valvecomponents 60 and 62 of connection or shut-off valve 27.

Similar to pressure-regulating valve 26, discussed above,pressure-regulating valve 126 includes a pressure sensitive diaphragm140. Diaphragm 140 is similar to diaphragm 96 described above. In thisembodiment, however, diaphragm 140 is sandwiched between two housingelements, a valve housing 146 and a valve cover 148, and has a hole 149formed through its center, as best seen in FIG. 4A. Additionally, a void129 is formed at the interface of valve housing 146 and valve cover 148to allow diaphragm 140 to move or flex due to the pressure differencebetween the inlet pressure at channel 143, the outlet pressure atchannel 145, and a reference pressure, Pref. Valve housing 146 has aninternal configuration that defines a flow path through regulator valve126. Specifically, channels 143 and 145 are formed in valve housing 146,where channel 143 is exposed to the inlet pressure and channel 145 isexposed to the outlet pressure. Further, a vent channel 141 is formed invalve cover 148 so that diaphragm 140 is exposed to the referencepressure, which may be atmospheric pressure.

Valve housing channel 143 is configured to slidingly receive a valvestem 142. Valve housing channel 143 is configured to narrow at or nearthe interface of valve housing 146 and valve cover 148 to form ashoulder 137. Valve stem 142 is preferably a unitary element having aslender stem portion 138 and a cap 131. This configuration allowsslender stem portion 138 to extend through the narrow portion of valvehousing channel 143 while cap 131 comes to rest against shoulder 137. Assuch, cap 131 and shoulder 137 both include sealing surfaces to closethe flow path through valve 126 at shoulder 137 when cap 131 is seatedthereagainst. Additionally, a grommet 147 secures valve stem 142 withinhole 149 in diaphragm 140, thereby creating a seal and a secureconnection between diaphragm 140 and valve stem 142. Therefore, asdiaphragm 140 moves, valve stem 142 also moves such that cap 131 isseated and unseated against shoulder 137 thereby opening and closingvalve 126.

When pressure-regulating valve 126 is positioned in conduit 88 ofgas-generating apparatus 12, reaction chamber pressure P₁₈ provides theoutlet pressure at channel 145 and reservoir pressure P₄₄ provides theinlet pressure at channel 143. When reaction chamber pressure P₁₈ islow, valve 126 is in an open configuration as shown in FIG. 4A, wherediaphragm is unflexed and cap 131 of valve stem 142 is unseated fromshoulder 137. As such, fluid fuel component 22 (shown in FIG. 1) flowsthrough valve 126 and into fluid dispersal element 89 (shown in FIG. 1),assuming that fluid transfer valve 33 is also open. The introduction offluid fuel component 22 to solid fuel component 24 starts the productionof fuel gas, which seeps through solid fuel container 23 (shown inFIG. 1) and into reaction chamber 18, as described above. Reactionchamber pressure P₁₈ begins to rise. The pressure within conduit 145rises with P₁₈ and translates into void 129. Reaction chamber pressureP₁₈ gradually increases with the buildup of fuel gas until thresholdpressure P₃₄ is reached and valve 34 (shown in FIG. 1) opens to allowthe flow of gas through fuel conduit 16 (shown in FIG. 1). Fuel gas isthen transferred out of reaction chamber 18. While this process mayreach a steady state, the production of gas may outpace the transfer ofgas through valve 34, or, alternatively, valve 34 or valve 27 may bemanually or electronically closed. In such a situation, reaction chamberpressure P₁₈ may continue to build until reaction chamber pressure P₁₈exceeds P_(ref), P₄₄ or (P₄₄ less P_(ref)) as no further gas istransferred from reaction chamber 18 with valve 34 (or valves 34, 27)closed. As a result of the rising reaction chamber pressure P₁₈,diaphragm 140 deforms toward valve cover 148. If reaction chamberpressure P₁₈ continues to rise, diaphragm 140 deforms toward valve cover148 to such an extent that cap 131 of valve stem 142 seats againstshoulder 137 to seal valve 126. As such, the flow of additional fluidfuel component is halted, which slows and eventually stops theproduction of fuel gas in reaction chamber 18.

If valve 34 remains open, fuel gas is transferred out of reactionchamber 18, which reduces the reaction chamber pressure P₁₈. Thisreduction in reaction chamber pressure P₁₈ is transferred to void 129 byconduit 145, and diaphragm 140 starts to return to its originalconfiguration as the pressure differential thereacross begins toequalize, i.e., P₁₈, P₄₄ and P_(ref) begin to balance. As diaphragm 140moves back into position, valve stem 142 is also moved, therebyunseating cap 131 from shoulder 137 to re-open valve 126. As such, fluidfuel component 22 is free to once again flow into reaction chamber 18.This cycle, which is similar to the cycle described in Table 1, repeatsuntil fluid transfer valve 33, fuel transfer valve 34, or anotherdownstream valve is closed by the operator or controller.

The pressure at which regulator/valve 126 opens or closes can beadjusted by adjusting the length of the valve stem or the gap that cap131 travels between the open and closed position and/or by adjustingPref. Stem 138 is sized and dimensioned to be movable relative togrommet 147 to adjust length of stem 138. The longer the length of stem138 between grommet 147 and cap 131, the higher the pressure needed toclose valve 126.

In the embodiment where pressure-regulating valve 126 is locateddownstream of reaction chamber 18, e.g., when valve 126 replaces valve34 or when valve 126 is connected to the fuel cell or the device thathouses the fuel cell, P₁₈ becomes the inlet pressure at channel 143 andthe outlet pressure at channel 145 is the pressure of the hydrogen fuelgas that the fuel cell would receive. Preferably, the outlet pressure issubstantially constant or is kept within an acceptable range, and thereference pressure, P_(ref), is selected or adjusted to provide such anoutlet pressure. In other words, P_(ref) is set so that when the inletpressure exceeds a predetermined amount, diaphragm 140 closes tominimize high or fluctuating outlet pressure at channel 145.

Another embodiment of a pressure-regulating valve 226 is shown in FIGS.4C and 4D. Pressure-regulating valve 226 is similar topressure-regulating valve 126 discussed above, as a valve housing 248 isattached to a valve cap 247. Formed in valve cap 247 is an inlet 243,while a pressure regulated outlet 245 is formed in valve housing 248. Ahole 251 is formed in a lower portion of valve cap 247. Preferably, hole251 is slightly off-center from the longitudinal axis ofpressure-regulating valve 226.

Sandwiched and retained between valve cap 247 and valve housing 248 is adeformable capped cylinder 250. Capped cylinder 250 includes an upperend 259, a lower end 287, and a hole or channel 201 formed therethrough.Capped cylinder 250 is made of any deformable, elastomeric materialknown in the art, such as rubber, urethane, or silicone. Capped cylinder250 functions similar to a pressure-sensitive diaphragm.

Upper end 259 is positioned adjacent valve cap 247 such that when nofluid flows through pressure-regulating valve 226 upper end 259 is flushagainst a lower surface of valve cap 247. The edges of upper end 259 arefixed in position so that even if the remainder of upper cap 259 flexes,the edges remain stationary and sealed.

Lower end 287 is positioned adjacent valve housing 248. A void 202 isformed in valve housing 248 and is positioned directly below lower end287 to allow lower end 287 to flex freely. Preferably, lower end 287 hasa different diameter than upper end 259, as explained below.

A retainer 253 made of a substantially rigid material surrounds cappedcylinder 250. Retainer 253 defines a hole 241 to connect a second void203 formed circumferentially between capped cylinder 250 and retainer253 with a reference pressure Pref. Portion 205 of second void 203 isconfigured to extend partially along and on top of lower cap 287.

To regulate pressure, inlet gas or liquid enters pressure-regulatingvalve through inlet 243 and passes into hole 251. Hole 251 can be acircular channel or ring defined on cap 247. Upper end 259 seals hole251 until the pressure exerted by the inlet gas or liquid from inlet 243reaches a threshold to deform upper end 259. When the gas deforms upperend 259, the deformation translates through the body of cylinder 250 toalso deform lower end 287. Once upper end 259 deforms, the gas is ableto pass through hole 251, through capped cylinder 250 and out regulatedoutlet 245.

Since the applied forces on capped cylinder 250 are the products of theapplied pressure times the area exposed to that pressure, the forcesacting on capped cylinder 250 can be summarized as follows:Inlet Force+Reference Force

Outlet Force (P at inlet 243·Area of upper end 259)+(Pref·Area ofportion 205)

(P at outlet 245·Area of lower end 287)When the outlet force is greater than the inlet and reference forces,then pressure-regulating valve 226 is closed, and when outlet force isless than the inlet and reference forces, the valve 226 is open. Since,in this embodiment the outlet force has to counter-balance both theinlet and reference forces, the area of lower end 287 is advantageouslymade larger than the area of upper end 259, as shown, so that the outletforce may be larger without increasing the outlet pressure. By varyingthe areas of ends 259 and 287 and portion 205, the balance of forces oncapped cylinder 250 can be controlled and the pressure differentialrequired to open and close valve 226 can be determined.

Since reference pressure P_(ref) tends to press down on lower end 287,this additional pressure can lower the threshold pressure to initiateflow, i.e., reference pressure P_(ref) is relatively high to assist thegas in deforming capped cylinder 250. Reference pressure P_(ref) may beadjusted higher or lower to further regulate the pressure of the gasleaving outlet 245.

FIGS. 5A-D shows a combination of a pressure-regulating valve 326 beingused with connection or shut-off valve 27. FIG. 5A showspressure-regulating valve 326 being mated to be in fluid communicationwith valve component 60 of connection valve 27. Pressure-regulatingvalve 326 is similar to pressure-regulating valves 126 and 226 describedabove, and has a spring-biased diaphragm 340. Diaphragm 340 is supportedby first piston 305, which is being biased by spring 306 toward secondpiston 307. First piston 305 is opposed by second piston 307 biased byspring 309, which biases piston 307 toward piston 305. A ball 311 isdisposed between spring 309 and second piston 307.

Springs 306 and 309 oppose each other, and, by balancing the forcesexerted by the two springs, the outlet pressure at channel 313 can bedetermined. Spring 309 does not act on or have any effect on spring 66of valve component 60. When valve component 60 is opened by mating withvalve component 62, shown in FIGS. 5B-5D, hydrogen fuel gas or otherfluids flows through valve component 60 and to inlet 315. If the fluidis hydrogen gas, then the hydrogen is transported to the fuel cell. Aflow path through valve 326 is established from inlet 315 through spring309, around ball 311, through the space between piston 307 and shoulder337 of housing 346, though orifice 337 of housing 346, and throughorifice 348 and outlet 313. In this embodiment, the space between piston307 and shoulder 337 is normally open to allow fluid to passtherethrough.

The pressure of the incoming fluid through inlet 315 or the pressure atoutlet 313, if sufficiently high, may overcome the resultant forcebetween springs 306 and 309 and move diaphragm 340 and pistons 305 and307 to the left as depicted in FIG. 5A. Spring 309 then biases ball 311to sealing member 319 to seal valve 326. To ensure that the flow of fuelfollows the preferred path, sealing member 317 may be provided.

In one embodiment, the force applied on diaphragm 340 and pistons 305and 307 can be adjusted. Spring 306 is adjustable by a rotationaladjusting member 321, which is secured by a threaded lock nut 321.Rotating adjusting member 321 in one direction further compresses spring306 to increase the force applied on the diaphragm and pistons, androtating in the opposite direction expands spring 306 to decrease theforce applied on the diaphragm and pistons. Additionally, a referencepressure, P_(ref), can be applied to channel 323 behind piston 305 toapply another force on piston 305.

FIG. 5B shows pressure regulator/valve 326 connected to valve component60 with valve component 62 not connected to valve component 60. FIG. 5Cshows regulator/valve 326 with valve components 60 and 62 partiallyengaged, but with no flow path established through valve components 60and 62. FIG. 5D shows regulator/valve 326 with valve components 60 and62 fully engaged with a flow path established through valve components60 and 62. In one embodiment, valve component 62 may be connected toconduit 16 of gas-generating apparatus 12, shown in FIG. 1, andregulator 326 replaces valve 34 and is connected to the fuel cell or thedevice. On the other hand, valve component 62 may be connected to thefuel cell or the device and regulator 326 and valve component 60 areconnected to the gas-generating apparatus or fuel supply. If a highpressure surges through valve 326, diaphragm 340 limits the amount offuel that can be transported through conduit 313.

Another embodiment of a pressure-regulating valve 426 is shown in FIGS.6A and B. Pressure-regulating valve 426 is similar topressure-regulating valve 226, discussed above, except that valve 426has a slidable piston 450 instead of flexible capped cylinder 250. Valve426 has valve housing 448 attached to a valve cap 447. Formed in valvecap 447 is an inlet 443, while a pressure regulated outlet 445 is formedin valve housing 448. A hole 451 is formed in a lower portion of valvecap 447. Preferably, hole 451 is slightly off-center from thelongitudinal axis of pressure-regulating valve 426. Hole 451 maycomprise a plurality of holes formed as a ring so that the inletpressure is applied uniformly on slidable piston 450.

Slidably disposed between valve cap 447 and valve housing 448 is aslidable piston 450. Slidable piston 450 includes an upper portion 459having a first diameter, a lower portion 487 having a second diameterwhich is preferably larger than the diameter of upper portion 459, and ahole 401 formed therethrough. Slidable piston 450 is made of any rigidmaterial known in the art, such as plastic, elastomer, aluminum, acombination of elastomer and a rigid material or the like.

A space 402 is formed in valve housing 448 to allow piston 450 to slidebetween cap 447 and housing 448. A second void 403 is formed betweenslidable piston 450 and valve housing 448. Void 403 is connected with areference pressure Pref. A portion 405 of void 403 is positionedopposite to lower end 487, so that a reference force can be applied onpiston 450.

Upper portion 459 is positioned adjacent valve cap 447 such that whenthe outlet force exceeds the inlet force and the reference force, asdiscussed above, upper portion 459 is flush against a lower surface ofvalve cap 447 to close valve 426, as shown in FIG. 6A. When the outletforce is less than the inlet and reference forces, piston 450 is pushedtoward housing 448 to allow fluids, such as hydrogen gas, to flow frominlet 443 through hole(s) 451 and hole 401 to outlet 445. Again, asdiscussed above with reference to valve 226, the surface areas of ends459 and 487, and of space 405 can be varied to control the opening andclosing of valve 426.

As will be recognized by those in the art, any of these valves may beused, either alone or in combination, to provide pressure-basedregulation of gas-generating apparatus 12. For example, valve 126, 226,326 or 426 can be used in place of valve 26, 33 or 34.

In accordance to another aspect of the present invention, a pre-selectedorifice is provided in conjunction with valve 126, 226, 326 and/or 426to regulate the pressure or volume of the fluid, e.g., hydrogen gas,exiting from the outlet of these valves. For example, referring to valve326, shown in FIG. 5A, orifice 348 is positioned upstream of outlet 313.In one aspect, orifice 326 acts as a flow restrictor to ensure that whenthe inlet pressure at inlet 315 or within pressure-regulating valve 326is high, orifice 348 sufficiently limits the outlet flow at 313 so thatthe high pressure can act on diaphragm 340, moving it to the left, toclose valve 326. An advantage of using flow restrictor/orifice 348 iswhen outlet 313 is open to a low pressure, e.g., atmospheric pressure,or open to a chamber that cannot hold pressure orifice 348 helps ensurethat diaphragm 340 would sense the inlet pressure.

Orifice 348 may also control the flow of fluid out of outlet 313. Whenthe range of inlet pressure at inlet 315 or pressure internal topressure-regulating valve 326 is known and the desirable flow rate isalso known, by applying flow equations for compressible fluid flow, suchas Bernoulli's equations (or using incompressible fluid flow equationsas a close approximation thereof) the diameter(s) of orifice 348 can bedetermined.

Additionally, the diameter of effective diameter of orifice 348 may varyaccording to inlet pressure at inlet 315 or internal pressure of valve326. One such variable orifice is described in commonly owned,co-pending U.S. Publ. Appl. No. US 2005/0118468, which is incorporatedherein by reference in its entirety. The '468 reference discloses valve(252) shown in FIGS. 6(a)-(d) and 7(a)-(k) and corresponding texts ofthat reference. The various embodiments of this valve (252) have reducedeffective diameter when flow pressure is high and have increasedeffective diameter when the flow pressure is lower.

Another variable orifice 348 is shown in FIGS. 7A and 7B. In thisembodiment, orifice 348 or another fluid conduit has a duckbill valve350 disposed therein with nozzle 352 facing the direction of fluid flow,as shown. The fluid's pressure acts on neck 354 and when the pressure isrelatively low the diameter of nozzle 352 is relatively large, and whenthe pressure is relatively high the diameter of nozzle 352 is relativelysmall to further restrict flow. When pressure is sufficiently high,nozzle 352 may be shut off.

Some examples of the fuels that are used in the present inventioninclude, but are not limited to, hydrides of elements of Groups IA-IVAof the Periodic Table of the Elements and mixtures thereof, such asalkaline or alkali metal hydrides, or mixtures thereof. Other compounds,such as alkali metal-aluminum hydrides (alanates) and alkali metalborohydrides may also be employed. More specific examples of metalhydrides include, but are not limited to, lithium hydride, lithiumaluminum hydride, lithium borohydride, sodium hydride, sodiumborohydride, potassium hydride, potassium borohydride, magnesiumhydride, calcium hydride, and salts and/or derivatives thereof. Thepreferred hydrides are sodium borohydride, magnesium borohydride,lithium borohydride, and potassium borohydride. Preferably, thehydrogen-bearing fuel comprises the solid form of NaBH₄, Mg(BH₄)₂, ormethanol clathrate compound (MCC) which is a solid and includesmethanol. In solid form, NaBH₄ does not hydrolyze in the absence ofwater and therefore improves shelf life of the cartridge. However, theaqueous form of hydrogen-bearing fuel, such as aqueous NaBH₄, can alsobe utilized in the present invention. When an aqueous form of NaBH₄ isutilized, the chamber containing the aqueous NaBH₄ also includes astabilizer. Exemplary stabilizers can include, but are not limited to,metals and metal hydroxides, such as alkali metal hydroxides. Examplesof such stabilizers are described in U.S. Pat. No. 6,683,025, which isincorporated by reference herein in its entirety. Preferably, thestabilizer is NaOH.

The solid form of the hydrogen-bearing fuel is preferred over the liquidform. In general, solid fuels are more advantageous than liquid fuelsbecause the liquid fuels contain proportionally less energy than thesolid fuels and the liquid fuels are less stable than the counterpartsolid fuels. Accordingly, the most preferred fuel for the presentinvention is powdered or agglomerated powder sodium borohydride.

According to the present invention, the fluid fuel component preferablyis capable of reacting with a hydrogen-bearing solid fuel component inthe presence of an optional catalyst to generate hydrogen. Preferably,the fluid fuel component includes, but is not limited to, water,alcohols, and/or dilute acids. The most common source of fluid fuelcomponent is water. As indicated above and in the formulation below,water may react with a hydrogen-bearing fuel, such as NaBH₄ in thepresence of an optional catalyst to generate hydrogen.X(BH₄)_(y)+2H₂O→X(BO)₂+4H₂Where X includes, but is not limited to, Na, Mg, Li and all alkalinemetals, and y is an integer.

Fluid fuel component also includes optional additives that reduce orincrease the pH of the solution. The pH of fluid fuel component can beused to determine the speed at which hydrogen is produced. For example,additives that reduce the pH of fluid fuel component result in a higherrate of hydrogen generation. Such additives include, but are not limitedto, acids, such as acetic acid and sulfuric acid. Conversely, additivesthat raise the pH can lower the reaction rate to the point where almostno hydrogen evolves. The solution of the present invention can have anypH value less than 7, such as a pH of from about 1 to about 6 and,preferably, from about 3 to about 5.

In some exemplary embodiments, fluid fuel component includes a catalystthat can initiate and/or facilitate the production of hydrogen gas byincreasing the rate at which fluid fuel component reacts with a fuelcomponent. The catalyst of these exemplary embodiments includes anyshape or size that is capable of promoting the desired reaction. Forexample, the catalyst may be small enough to form a powder or it may beas large as the reaction chamber, depending on the desired surface areaof the catalyst. In some exemplary embodiments, the catalyst is acatalyst bed. The catalyst may be located inside the reaction chamber orproximate to the reaction chamber, as long as at least one of eitherfluid fuel component or the solid fuel component comes into contact withthe catalyst.

The catalyst of the present invention may include one or moretransitional metals from Group VIIIB of the Periodic Table of Elements.For example, the catalyst may include transitional metals such as iron(Fe), cobalt (Co), nickel (Ni), ruthenium (Ru), rhodium (Rh), platinum(Pt), palladium (Pd), osmium (Os) and iridium (Ir). Additionally,transitional metals in Group IB, i.e., copper (Cu), silver (Ag) and gold(Au), and in Group IIB, i.e., zinc (Zn), cadmium (Cd) and mercury (Hg),may also be used in the catalyst of the present invention. The catalystmay also include other transitional metals including, but not limitedto, scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr) andmanganese (Mn). Transition metal catalysts useful in the presentinvention are described in U.S. Pat. No. 5,804,329, which isincorporated by reference herein in its entirety. The preferred catalystof the present invention is CoCl₂.

Some of the catalysts of the present invention can generically bedefined by the following formula:M_(a)X_(b)

wherein M is the cation of the transition metal, X is the anion, and “a”and “b” are integers from 1 to 6 as needed to balance the charges of thetransition metal complex.

Suitable cations of the transitional metals include, but are not limitedto, iron (II) (Fe²⁺), iron (III) (Fe³⁺), cobalt (Co²⁺), nickel (II)(Ni²⁺), nickel (III) (Ni³⁺), ruthenium (III) (Ru³⁺), ruthenium (IV)(Ru⁴⁺), ruthenium (V) (Ru⁵⁺), ruthenium (VI) (Ru⁶⁺), ruthenium (VIII)(Ru⁸⁺), rhodium (III) (Rh³⁺), rhodium (IV) (Rh⁴⁺), rhodium (VI) (Rh⁶⁺),palladium (Pd²⁺), osmium (III) (Os³⁺), osmium (IV) (Os⁴⁺), osmium (V)(Os⁵⁺), osmium (VI) (Os⁶⁺), osmium (VIII) (OS⁸⁺), iridium (III) (Ir³⁺),iridium (IV) (Ir⁴⁺), iridium (VI) (Ir⁶⁺), platinum (II) (Pt²⁺), platinum(III) (Pt³⁺), platinum (IV) (Pt⁴⁺), platinum (VI) (Pt⁶⁺), copper (I)(Cu⁺), copper (II) (Cu²⁺), silver (I) (Ag⁺), silver (II) (Ag²⁺), gold(I) (Au⁺), gold (III) (Au³⁺), zinc (Zn²⁺), cadmium (Cd²⁺), mercury (I)(Hg⁺), mercury (II) (Hg²⁺), and the like.

Suitable anions include, but are not limited to, hydride (H⁻), fluoride(F⁻), chloride (Cl⁻), bromide (Br⁻), iodide (I⁻), oxide (O²⁻), sulfide(S²⁻), nitride (N³⁻), phosphide (P⁴⁻), hypochlorite (ClO⁻), chlorite(ClO₂ ⁻), chlorate (ClO₃ ⁻), perchlorate (ClO₄ ⁻), sulfite (SO₃ ²⁻),sulfate (SO₄ ²⁻), hydrogen sulfate (HSO₄ ⁻), hydroxide (OH⁻), cyanide(CN⁻), thiocyanate (SCN⁻), cyanate (OCN⁻), peroxide (O₂ ²⁻), manganate(MnO₄ ²⁻), permanganate (MnO₄ ⁻), dichromate (Cr₂O₇ ²⁻), carbonate (CO₃²⁻), hydrogen carbonate (HCO₃ ⁻), phosphate (PO₄ ²⁻), hydrogen phosphate(HPO₄ ⁻), dihydrogen phosphate (H₂PO₄ ⁻), aluminate (Al₂O₄ ²⁻), arsenate(AsO₄ ³⁻), nitrate (NO₃ ⁻), acetate (CH₃COO⁻), oxalate (C₂O₄ ²⁻), andthe like. A preferred catalyst is cobalt chloride.

In some exemplary embodiments, the optional additive, which is in fluidfuel component and/or in the reaction chamber, is any composition thatis capable of substantially preventing the freezing of or reducing thefreezing point of fluid fuel component and/or solid fuel component. Insome exemplary embodiments, the additive can be an alcohol-basedcomposition, such as an anti-freezing agent. Preferably, the additive ofthe present invention is CH₃OH. However, as stated above, any additivecapable of reducing the freezing point of fluid fuel component and/orsolid fuel component may be used.

Other embodiments of the present invention will be apparent to thoseskilled in the art from consideration of the present specification andpractice of the present invention disclosed herein. For example, any ofthe valves herein may be triggered by an electronic controller such as amicroprocessor. A component of one valve can be used with another valve.Also, a pump may be included to pump the fluid fuel component into thereaction chamber. It is intended that the present specification andexamples be considered as exemplary only with a true scope and spirit ofthe invention being indicated by the following claims and equivalentsthereof.

1. A gas-generating apparatus comprising: a gas-impermeable housing; afuel container having at least one gas-permeable wall surrounding afirst fuel component, wherein the fuel container is located at leastpartially within the gas-impermeable housing; a reservoir containing aliquid fuel component; and a fluid path for introducing the liquid fuelcomponent to the first fuel component within the fuel container to reactto produce a gas, wherein the at least one gas-permeable wall of thefuel container comprises a fibrous absorbent layer disposed between aninner layer and an outer layer, wherein at least one of the inner layerand outer layer comprises a liquid-impermeable layer material having atleast one opening formed therethrough, a third liquid-impermeable layerhaving at least one opening disposed outside of said outer layer whereinthe at least one opening in the third layer is located away from the atleast one opening in the outer layer.
 2. A gas-generating apparatuscomprising: a gas-impermeable housing; a fuel container having at leastone gas-permeable wall and containing a first fuel component, whereinthe fuel container is located at least partially within thegas-impenneable housing; a reservoir containing a liquid fuel component;and a fluid path for introducing the liquid fuel component into theinterior of the first fuel component within the fuel container to reactto produce a gas, wherein the fuel container comprises at least onefluid dispersal tube, so that the liquid fuel component is introduced atat least one discrete point, and wherein said dispersal tube comprisesan annular space between said dispersal tube and an inner rod to conductflow therethrough and wherein the dispersal tube and inner rod arepermanently fixed relative to each other.
 3. The gas-generatingapparatus of claim 1, wherein the fluid path comprises a valve thatopens and closes relative to the pressures of the housing and thereservoir.
 4. The gas-generating apparatus of claim 2 further comprisinga pressure-regulating valve operatively associated with the fluid path.5. The gas-generating apparatus of claim 4, wherein thepressure-regulating valve comprises a pressure-responsive diaphragm. 6.The gas-generating apparatus of claim 5, wherein the diaphragm is biasedby an energy storage element.
 7. The gas-generating apparatus of claim6, wherein the energy storage element comprises a spring.
 8. Thegas-generating apparatus of claim 6, wherein the energy storage elementcomprises a reference pressure.
 9. The gas-generating apparatus of claim5, wherein the diaphragm is in communication with the fuel container.10. The gas-generating apparatus of claim 5, wherein the diaphragm isconnected to a sealing member.
 11. The gas-generating apparatus of claim10, wherein the sealing member is adjustable to vary the pressure thatseals the pressure-regulating valve.
 12. The gas-generating apparatus ofclaim 2 further comprising: a first pressure-sensitive valve forcontrolling a flow of the liquid fuel component to the second fuelcomponent; and a second pressure-sensitive valve for controlling a flowof the gas out of the gas-generating apparatus.
 13. The gas-generatingapparatus of claim 12, wherein when a pressure of the gas is greaterthan a first predetermined amount, the first pressure-sensitive valvecloses the fluid path.
 14. The gas-generating apparatus of claim 13,wherein when the pressure of the gas is less than a second predeterminedamount, the second pressure-sensitive valve closes the flow of gas outof the gas-generating apparatus.
 15. The gas-generating apparatus ofclaim 14, wherein when the pressure of the gas is greater than thesecond predetermined amount, the second pressure-sensitive valve opensthe flow of gas out of the gas-generating apparatus.
 16. Thegas-generating apparatus of claim 14, wherein when the pressure of thegas is less than the first predetermined amount, the firstpressure-sensitive valve opens the fluid path.
 17. The gas-generatingapparatus of claim 12, wherein when the liquid fuel component ispressurized.
 18. The gas-generating apparatus of claim 12, wherein thefirst pressure-sensitive valve comprises a check valve, a duckbillvalve, or a diaphragm valve.
 19. The gas-generating apparatus of claim12, wherein the first pressure-sensitive valve comprises a pressuresensitive diaphragm.
 20. The gas-generating apparatus of claim 19,wherein the diaphragm is supported by an energy-storage device.
 21. Thegas-generating apparatus of claim 19, wherein the firstpressure-sensitive valve comprises a globe seal.
 22. The gas-generatingapparatus of claim 21, wherein the first pressure-sensitive valvefurther comprises a check valve, a duckbill valve, or a diaphragm valve.23. The gas-generating apparatus of claim 12, wherein the secondpressure-sensitive valve comprises a check valve, a duckbill valve or apressure regulating valve.
 24. The gas-generating apparatus of claim 12,wherein the liquid fuel component comprises water.
 25. Thegas-generating apparatus of claim 12, wherein said another fuelcomponent comprises a hydride.
 26. The gas-generating apparatus of claim1 further comprising: a pressure cycling system, wherein the pressurecycling system regulates a flow of the liquid fuel component to saidanother fuel component based on at least a pressure of the gas in saidanother fuel component, and wherein the pressure cycling systemregulates a flow of the gas out of the gas-generating apparatus based onat least the pressure of the gas.
 27. The gas-generating apparatus ofclaim 26, wherein the pressure cycling system comprises a first valveand a second valve, wherein the first valve regulates a flow of theliquid fuel component to the second fuel component and wherein thesecond valve regulates a flow of the gas out of the gas-generatingapparatus.
 28. The gas-generating apparatus of claim 27, wherein thefirst valve and the second valve are pressure-sensitive valves.
 29. Thegas-generating apparatus of claim 26, wherein said another fuelcomponent is a hydride.
 30. The gas-generating apparatus of claim 26,wherein the liquid fuel component comprises water.
 31. Thegas-generating apparatus of claim 26, wherein the liquid fuel componentis pressurized.
 32. The gas-generating apparatus of claim 26, whereinthe fluid path introduces the liquid fuel component into the inside ofsaid another fuel component.
 33. The gas-generating apparatus of claim1, wherein another absorbent layer is disposed between the intermediatelayer and the third layer.
 34. The gas-generating apparatus of claim 2,wherein said dispersal tube comprises a plurality of discrete points.